Haskell. Windows are managed using automatic layout algorithms,
which can be dynamically reconfigured. At any time windows are
arranged so as to maximise the use of screen real estate. All
features of the window manager are accessible purely from the
keyboard: a mouse is entirely optional. Xmonad is configured in
Haskell, and custom layout algorithms may be implemented by the user
in config files. A principle of Xmonad is predictability: the user
should know in advance precisely the window arrangement that will
result from any action.

This package comes pre-configured with the default configuration. If
you want to build your custom-configured version, make sure that
libghc6-xmonad-dev is installed and put your configuration in
~/.xmonad/xmonad.hs

/usr/share/doc/xmonad/README.Debian

xmonad packages for debian
==========================
The packages for debian are split as follows:
* xmonad
This package contains only the xmonad binary (with it’s man page) in the
default configuration. You do not have to install the haskell compiler to
use this package, but you also cannot reconfigure it to your needs. To do
that, you need the libghc6-xmonad-dev package. If that is
more»

/usr/share/doc/xmonad/README.gz

xmonad : a tiling window manager
http://xmonad.org
xmonad is a tiling window manager for X. Windows are arranged
automatically to tile the screen without gaps or overlap, maximising
screen use. Window manager features are accessible from the
keyboard: a mouse is optional. xmonad is written, configured and
extensible in Haskell. C
more»

/usr/share/man/man1/xmonad.1.gz

xmonad(1) xmonad manual xmonad(1)
xmonad - a tiling window manager
Description
xmonad is a minimalist tiling window manager for X, written
in Haskell. Windows are managed using automatic layout algo‐
rithms, which can be dynamically reconfigured. At any time
windows are arranged so as to maximize the use of screen re
more»